fbdev: omapfb: Make FB_DEVICE dependency optional

omapfb provides several sysfs interfaces for framebuffer configuration
and debugging, but these are not required for the core driver.

Remove the hard dependency on CONFIG_FB_DEVICE and make sysfs support
optional by using dev_of_fbinfo() to obtain the backing device at runtime.
When FB_DEVICE is disabled, sysfs operations are skipped while the code
still builds and is type-checked.

Suggested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Chintan Patel <chintanlike@gmail.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>

Author: nehudesi

drivers/video/fbdev/omap2/omapfb/Kconfig

@@ -5,14 +5,15 @@ config OMAP2_VRFB
 menuconfig FB_OMAP2
 	tristate "OMAP2+ frame buffer support"
 	depends on FB
-	depends on FB_DEVICE
 	depends on DRM_OMAP = n
 	depends on GPIOLIB
 	select FB_OMAP2_DSS
 	select OMAP2_VRFB if ARCH_OMAP2 || ARCH_OMAP3
 	select FB_IOMEM_HELPERS
 	help
 	  Frame buffer driver for OMAP2+ based boards.
+	  FB_DEVICE is not required, but if enabled, provides sysfs interface
+	  for framebuffer configuration and debugging.
 
 if FB_OMAP2
 

drivers/video/fbdev/omap2/omapfb/omapfb-sysfs.c

@@ -558,10 +558,15 @@ int omapfb_create_sysfs(struct omapfb2_device *fbdev)
 
 	DBG("create sysfs for fbs\n");
 	for (i = 0; i < fbdev->num_fbs; i++) {
+		struct device *dev;
 		int t;
+
+		dev = dev_of_fbinfo(fbdev->fbs[i]);
+		if (!dev)
+			continue;
+
 		for (t = 0; t < ARRAY_SIZE(omapfb_attrs); t++) {
-			r = device_create_file(fbdev->fbs[i]->dev,
-					&omapfb_attrs[t]);
+			r = device_create_file(dev, &omapfb_attrs[t]);
 
 			if (r) {
 				dev_err(fbdev->dev, "failed to create sysfs "
@@ -580,9 +585,14 @@ void omapfb_remove_sysfs(struct omapfb2_device *fbdev)
 
 	DBG("remove sysfs for fbs\n");
 	for (i = 0; i < fbdev->num_fbs; i++) {
+		struct device *dev;
+
+		dev = dev_of_fbinfo(fbdev->fbs[i]);
+		if (!dev)
+			continue;
+
 		for (t = 0; t < ARRAY_SIZE(omapfb_attrs); t++)
-			device_remove_file(fbdev->fbs[i]->dev,
-					&omapfb_attrs[t]);
+			device_remove_file(dev, &omapfb_attrs[t]);
 	}
 }